1. Field of Invention
This invention relates generally to thermotherapy, and in particular to a high-power corona discharge thermotherapy system for relieving pain and obtaining other salutary effects in relatively large animals, in which the skin surface of the animal being treated overlying a problem region is subjected to a corona discharge beam derived from periodic bursts of radio-frequency energy whose repetition rate is at a sonic frequency.
2. Status of Prior Art
The term "problem region" as used herein refers to a set of muscles, an arthritic joint or any other region underlying the skin of an animal which is causing difficulty and which lends itself to treatment by thermotherapy.
Of greatest prior art interest is the Di Mino U.S. Pat. No. 4,667,677, which discloses a unit for generating a corona discharge beam and for projecting this beam toward the skin surface of a living body (human or animal) overlying a problem region, the beam serving to relieve pain and gain other salutary effects. The Di Mino unit includes a radio-frequency carrier generator which is overmodulated with an audio-frequency signal to produce periodic bursts of radio-frequency energy whose repetition rate corresponds to the frequency of the signal. These bursts are stored in a tank circuit coupled to the output of the modulated radio-frequency carrier generator. Connected by a short cable to the output of the tank circuit is a hand-held discharge electrode from which is projected a corona discharge beam, the electrode being manipulated by the operator to scan the skin surface to be treated.
Our above-identified copending application is directed to an improvement over the unit disclosed in the Di Mino patent. In this improvement, the output of the unit is fed by a flexible coaxial cable to a tank circuit tuned to the carrier frequency and housed within the barrel of a portable applicator gun on whose grip is mounted a trigger switch operatively connected to the unit. Supported within the barrel and coupled to the tank circuit is a relatively short and straight discharge electrode whose tip is adjacent the mouth of the barrel. When an operator holding the gun actuates the trigger switch, the unit is turned out and a corona discharge beam is then projected from the electrode tip, the operator positioning the gun to direct the beam toward the skin surface to be treated.
The power output of the system disclosed in our copending application is relatively low (i.e., 5 to 15 watts). And while we have found this system to be highly effective in treating human patients, it is less efficacious when used on large animals, such as horses, for such treatment requires a corona beam of greater strength.
In seeking to meet this requirement, we increased the power of the system to a level above 25 watts, such as 40 or 50 watts, well above the power appropriate for human patients. But we found that the resultant corona discharge beam was still not of adequate strength. However, by providing a much longer electrode (approximately 9 inches in length), the resultant strength of the corona discharge beam was brought up to an acceptable level.
This elongated electrode presented a problem, for it could not be included in the barrel of the portable applicator gun disclosed in our copending application. The reason for this is that the barrel housed the tank circuit of the system, and the only way we could include an elongated straight electrode in the barrel and couple it to the tank circuit was to greatly increase the length of the barrel so that it would accommodate the electrode. A barrel of this length would result in an applicator rifle, not a gun, and would be altogether impractical, for it is essential that the applicator be easily manipulated by the operator.